The most common is Ventricular septal defect. It is 20% of all congenital heart defects in newborns and 2 to 7 percent of babies are born with it. Ventricular septal defect are holes in the infants heart, located in the lower chambers. Doctors tend to diagnos VSD based on a heart murmur that can be heard with a stethoscope. Depending on the size of the holes, most babies survive the condition.